Ignition system unit



Jan 21, 947 J. R. HARKNEss vx-z-r AL. 2.434,69?

IGNITION SYSTEM UNIT FiledNm. 2s, 1942 Inventors: Joseph R Harkness, Arthur W. Robf'nsonl JT?, f

Their Attorney.

Patented Jan. 21, 1947 IGNITION SYSTEM UNIT Joseph R. Harkness and Arthur W. Robinson, Jr.,

Schenectady, N. Y., assignors to General Electric Company, a corporation of New York Application November 23, 1942, Serial No. 466,608

7 Claims.

Our invention relates to ignition system units and more particularly te combined transformer and spark discharge units.

yAn object of our invention is to provide an improved ignition unit including a, transformer provided with spark discharge electrodes.

Another object of our invention is to provide an improved lignition transformer unit.

Further objects and advantages of our invention will become apparent and our invention will be betterY understood from the following description referring to the accompanying drawing, and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming part oi this specification.

In the drawing, Fig. 1 is a side elevational view of an ignition unit, partly broken away, showing an embodiment of our improved transformer spark discharge unit; Fig. 2 is a, fragmentary sectional view showing a modification of the construction shown in Fig. l; and Fig. 3 is a side elevational view, partly broken away, showing another embodiment of our invention.

Referring to the drawing, we have shown an embodiment of our improved ignition unit in which spark discharge electrodes are arranged as in a, conventional spark plug and adapted to be energized by an electrical charge supplied to the central electrode by a transformer connected to a suitable source of electrical power supply. The spark discharge electrodes include a plurality of electrodes I electrically connected to the lower threaded portion I I of a conventional spark plug barrel I2. The upper part of the barrel I2 is threaded at I3 and an outer barrel sleeve element I4 threadedly engages the portion I3 and is tightly screwed down against a washer I5 to provide a fluid-tight seal between the barrel sleeve I4 and the barrel portion I2. Another barrel sleeve i5 is tightly iitted over the upper portion of the sleeve I4 and is welded or otherwise securedv there'- to at the lower edge I1 of the sleeve I6. A second' spark electrode I8 of the conventional spark plug type is arranged within the lower barrel portion I2 and is insulated therefrom and supported thereon by a suitable ceramic insulator I9 such as is conventionally used in spark plugs. The upper end of the electrode I8 is turnedl over to provide a Contact terminal head 2B. An ele-ctrical charge is adapted to be supplied to the spark electrode I8 at a relatively high electrical potential by a transformer unit arranged within the upper portion of the barrel sleeve It, This transformer includes a relatively low voltage, high current primary winding 2l which is wound about a sleeve 22 of any suitable insulating material, such as a ceramic or a heat-hardenable plastic material such as a thermo-'setting silicone resin. The insulating sleeve 22 is supported within the upper portion i3 of the barrel portion I2 and arranged between this portion I3 of the barrel and the upper end of the ceramic insulator I9. A suitable sealing cementing material 23 is arranged between the insulating sleeve 22 and the ceramic insulator I9 to secure the sleeve 22 in position and to form a duid-tight seal with the insulator I9. One end or terminal 24 of the primary winding is electrically connected to the barrel portion I3 and the other end 25 of the primary winding extends through an insulating member 26 and is secured to a terminal 2l ha ing a threaded portion 28 about which the insulating member 26 is molded. The terminal eiement 2? is formed as a clip and is arranged in engagement with the head of a terminal screw 29 which extends through an insulating member 321* formed of a suitable material, such as a heathardenable resin. The end of the screw 29 is arranged in intimate engagement with the end of a distribution lead conductor 3l which extends thro-ugh a terminal bushing 32 in the insulator 33. This provides a good electrical connection between the end of the distribution lead SI and the end 25 of the transformer primary winding through the screw terminal 29 and the clip terminal 2l. The distribution lead 3| is provided with insulation 32- and extends within a pocket 33 formed in the upper end of the insulating member 30.- A metallic elbow 34 is arranged about the endv of the distribution lead and is provided with a sealing sleeve 35 formed with a radially outwardly extending flange 36 at the lower end thereof.

Itis desirable that' the space in the barrel within which the transformer is arranged should be maintained at a predetermined pressure, preferably higher than ten pounds per Square inch absolute. It has been found that sea level atmospheric pressure of the air or other fluid about the transformer within the barrel is very satisfactory, and it is desirable, therefore, that the space with in the barrel about the transformer should be adequately sealed to insure that the pressure therein will remain at the desired value. This space is sealed at the lower end by the construction of the spark plug portion of the unit and sealed at the upper end thereof by providing a series of sealing bushing elements and threaded connections. A bushing 31 is arranged between 'the upper end of the insulating sleeve 22 and a flange 38 formed on the upper end of the insulating member 35. Another bushing 39 is arranged between the upper side of the insulator flange 38 and the lower edge of a mounting 'out 69 in the form of a threaded sleeve arranged in threaded engagement with the inner threaded upper portion 4| of the barrel sleeve portion H5. The upper end 42 of the nut lll is castellated so that the nutcan be drawn up tightly into engagement with the bushing 39 which holds the insulator and the bushing 37 in position on the upper end of the transformer insulating sleeve 22, A fluid seal is provided at the upper end of the chamber by a ange 43 formed on the insulator 39 arranged in engagement with sharp edges of ribs il formed on the upper edge of the barrel i6 and the sharp edges of ribs i5 formed on the lower surface of the ange 35. These sharp edges of the ribs de and 45 are drawnvinto intimate engagement with? the insulating member flange i3 byl a nut E9 which threadedly engages the outer threads i7 formed adjacent the upper end of the barrel sleeve l5. When the nut 49 is drawnl up tightly, it engages the upper surface of the flange and presses the sharp edged rib i5 intothe upper surface of the insulating flange i3 and presses the under surface of this flange over the sharp edges of the ribs dil, thereby forming a substantially fluid-tight seal.

In order to provide the desired electrical potential between the spark discharge electrodes I0 and i8, the transformer is provided with a secondary winding 68 wound about the lower portion of the insulator 25 and arranged within the insulating sleeve 22.- The insulator 2B is formed with a cavity 49 in its central portion and a core 59 of magnetic material is inserted into the cavity 49 and cemented therein by any suitable cement 5|.

The core 59 also is retained in position by a spring clip 52 which is arranged within the lower end of the cavity 99 in engagement with a shoulder 53 formed on the core 50 and in engagement with .the sides of the cavity 49. This spring clip is formed as a split ring which is compressed in order to make it t within the cavity 49. The seclondary Winding 98 of the transformer is electrically connected to the central spark electrode I8 through the spring clip 52 which is electrically -connected to the lower ende53 of the transformer 4secondary winding 68 and forms an electrical connection with the electrode head 29 through a spring nger 54 formed on the Alower edge of the spring clip 52. This provides a complete ignition unit which includes transformer primary and secondary windings with a suitable core and ignition each other by an insulating sleeve `22 arranged Y about a central insulator 26 within which a core 59 of magnetic material is supported. The upper terminals 55 and 56 of the transformer primary and secondary windings 2| and 48, respectively, are connected together to a terminal rod member 57 secured in the upper end of the insulator 2B by a threaded portion 58, about which the insulator 26 is molded. The upper end of the terminal rod 57 extends through a sleeve 59 of electrically the terminal rod 57. The space within the barrel about the transformer is effectively sealed by an insulator comprising a glass-to-metal seal formed by a glass element 6| fused to the o-uter side of the lower end of the sleeve 59 and to a dishshaped metallic washer 62. The outer edges of the washer 92 are welded at 63 to the upper edge of the barrel sleeve i6 to provide a fluid-tight seal therewith. The transformer assembly is retained in assembled relationship by a nut lIl Which threadedly engages threads B5 on the inner surface of the upper end of the barrel sleeve i6 and is drawn up tightly against a flange 66 formed on the lower edge of an insulating sleeve 67 and arranged in engagement with the upper edge of the transformer insulator 2B and the 10W- er edge of the nut 6a. This insulating sleeve 67 also insulates the nut 62 from the transformer conductive material which is sealed at its upper terminals 55 and 55. The desired electrical charge is supplied to the transformer from a source 0f electrical power supplyl 'such as a magneto, by a distribution lead 68 which is arranged in engagement with a spring clip finger 69 of a terminal 7i) arranged in electrical contact with the transformer terminal sleeve 59 withinan insulating member 7|. The insulating member 7| is arranged within an elbow 72 secured to the upper end of the barrel sleeve |19 by a gasket 73 arranged in a groove 74 in the elbow 72 and ina groove 75 in a nut 76 which threadedly engages threads 77 on the upper end of the barrel sleeve I6. The other end of the elbow 72 is connected to the shielding armor 78 by a nut 79 having a ange 89 which engages a flange 8| on the armor 78 so as to clamp it into engagement with an insulating washer 82 arranged between the armor ange 8| and a ange 89 on the end of the insulator 7 l.

In Fig. 3, we have shown another embodiment of our invention wherein the ignition unit is provided with spark discharge electrodes lll and IB supported within a barrel portion. l2 similar to the construction shown in Fig. 1. In this arrangement, the transformer is sealed in a space in the barrel by having the lowerend ofthe space sealed in a manner similar to that of Fig. 1 andv is arrangedwithin a barrel sleeve 90 welded at 9| to a flangeV 92 formed on the barrel portion |2. The upper end of the space about the 4transformer is adapted to be sealed by an eX- pansible glass-to-metal seal which includes an eXpansible metallic U-section washer 93 welded at 94 to the upper end of the barrel sleeve 99 and fused to a glass gasket element 95'which in turn is fused to an electrically conductive tube 96 extending through the central portion thereof. The metallic tube 96 is electrically connected to the transformer primary terminal lead 97 by being welded thereto at 98 at the upper end of the tube which also provides a fluid-tight seal at this end of the tube. The transformer secondary winding also is electrically connected to the tube 96 by being brazed at 99 to the primary terminal lead 97. The transformer construction is essentially the same as that shown in Fig. l. An elec'- trical charge is supplied to the spark electrodes i9 and i8 through the transformer by connecting the terminal tube 96 to a distribution lead |99 which is electrically connected at I9! to a terminal |92 Vsecured within an insulator |93 in a manner similar to that shown in Fig. 1. The lower end of the terminal |92 is formed with spring fingers |93 which engage the upper end of the terminal tube 96 and provide a good electrical connection therewith. The ignition unit and the lead armor l M about the distribution lead |00 are secured together by a nut IBS which threadedly engages threads itt formed on the outer surface of the upper end of the barrel sleeve 95. By drawing up the nut iil, a flange lill thereon clamps a flange itil on the distribution lead armor lllt into tight engagement with a flange i053 formed on the terminal insulator |03 against the upper side of the welded portion of the bushing element 93. This construction is somewhat more simple than that shown in Figs. 1 and 2 and will be found to be preferable Where the insulating medium about the transformer may have a larger change in volume due to expansion and contraction thereof at various temperatures oi the ignition unit. In each arrangement the space about the transformer may be lled with any desired suitable insulation, such as gases, liquids, or solids.

While we have illustrated and described particular embodiments of our invention, modifications thereof will occur to those skilled in the art. We desire it to be understood, therefore, that our invention is not to be limited to the particular arrangements disclosed, and we intend in the appended claims to cover all modications which do not depart from the spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. An ignition unit including a metallic barrel, a spark electrode connected to said barrel, a second spark electrode insulated from said barrel and providing a spark discharge gap with said firstmentioned electrode, a transformer' having a primary winding and a seconda-ry Winding mounted in a space in said barrel, means for connecting said secondary winding to said second spark electrode, means including a glass-to-metal seal at one end of said transformer space for sealing the space within said barrel about said transformer for substantially maintaining a pressure therein above ten pounds per square inch absolute, and means .for providing an electrical connection between an electrical conductor arranged externally of said glass seal and said transformer primary winding.

2. fin ignition unit including a barrel, a spark electrode connected to said barrel, a second spark electrode insulated from said barriel and providing aspark discharge gap With said first-mentioned electrode, a transformer having a primary winding and a secondary winding mounted in said barriel, an insulating element about which said secondary winding is wound, al core of magnetic material within said insulating element, means including a spring clip for retaining said core in position and for connecting said secondary winding to said second spark electrode, expansible means for sealing the space within said barrel about said transformer for substantially maintaining a predetermined pressure therein, and means for providing an electrical connection between an electrical conductor arranged externally of said sealed space and said transformer primary winding.

3. An ignition unit including a barrel, a spark electrode connected to said barrel, a second spark electrode insulated from said barrel and providing a spark discharge gap with said first-mentioned electrode, a, transformer having a primary Winding and a secondary Winding mounted in said barrel, an insulating element about which said secondary winding is Wound, a core of magnetic material Within said insulating element,

means including a spring clip arranged in engagement with said core and said insulating element for retaining said core in position and having an electrical connection with said secondary winding and said second spark electrode, means for sealing the space within said barrel about said transformer for substantially maintaining a predetermined pressure therein, and means for providing an electrical connection between an electrical conductor arranged externally of said sealed space and said transformer primary winding.

Ll. An ignition unit including a barrel, a spark electrode electrically connected to said barrel, a second spark electrode insulated from said barrel and providing a spark discharge gap with said inst-mentioned electrode, a transformer having a primary winding and a secondary winding mounted in a space in said barrel, an insulating element about which said secondary winding is wound, a core of magnetic material within said insulating element, means including a spring clip arranged in engagement with said core and said insulating element for retaining said core in position and having an electrical connection with said secondary winding and said second spark electrode, means including a glass-to-metal seal at one end of said transformer space for sealing the space within said barrel about said transformer for substantially maintaining a predetermined pressure therein, and means extending through said seal for providing an electrical connection between an electrical conductor arranged externally of said sealed space and said transformer primary winding.

5. An ignition unit including a metallic barrel, a spark electrode connected to said barrel, a second spark electrode insulated from said barrel and providing a spark discharge gap with said first-mentioned electrode, a transformer having a primary winding and a secondary winding mounted in a space in said barrel, means for connecting said secondary winding to said second spark electrode, expansible means including a glass-to-metal seal at one end of said transformer space for sealing the space within said barrel about said transformer for substantially maintaining a pressure therein above ten pounds per square inch absolute, and means for providing an electrical connection between an electrical conductor arranged externally of said glass seal and said transformer primary Winding.

6. A transformer having a primary winding and a secondary winding, an insulating spacer element arranged between said windings, a second insulating element about which said secondary winding is wound, a core of magnetic material within said second insulating element, and means including a spring clip arranged in engagement with said core and said second insulating element for retaining said core in position and providing a terminal for said secondary winding.

7. A transformer having a primary winding and a secondary winding, an insulating spacer element arranged between said windings, a second insulating element about which said secondary winding is wound having a central cavity therein, a core of magnetic material within said cavity in said second insulating element, and means including a spring clip arranged in engagement with said core and the sides of said cavity in said second insulating element for retaining said core in position therein.

JOSEPH R. HARKNESS. ARTHUR W. ROBINSON, J R. 

